23 Jul 2024


Software compensates for cogging effects in linear motors

Beckhoff’s cogging compensation software is designed for use with its AL8000 linear servomotors

The German automation specialist Beckhoff has developed a software tool that makes it possible to use linear motors for precision applications such as milling or laser-cutting machines. The software uses machine learning to compensate for the uneven cogging forces that have previously limited the use of linear motors in applications of this type.

The unwanted cogging forces are caused by the magnetic attraction between the iron core in the motor’s primary and the permanent magnets in the secondary. The new software takes into account not only these magnetic effects, but also those of energy chains and the application’s mechanical design. As a result, it expands the range of potential applications for iron-core linear motors “significantly”, according to Beckhoff.

The compensation tool is based on the automated application of machine learning in Beckhoff’s TwinCat software and is designed to be used with the company’s AL8000 linear servomotors. The software records the cogging data in an application during a reference run over the entire length of the motor’s magnetic track. Using this data, it trains a neural network, which is integrated with the control system for current pre-control. By adapting the current pre-control in this way, the lag error can be reduced by a factor of up to seven, while the synchronisation of the machine increased up to five-fold without needing any hardware changes to the linear motor.

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